CAMPBELLTON (March 17, 2010)--The Department of Public Safety Wednesday identified the two people who died when a tour bus bound for Mexico rolled on Interstate 37 south of San Antonio as Christina Lozano Campos, 62, of Lewisville and Efrain Dominguez-Valenzuela, 27, of Brownsville.

DPS spokeswoman Tela Mange says both were pronounced dead at the scene Tuesday.

The other 40 people on the bus were taken to San Antonio-area hospitals.

A spokeswoman for University Hospital said six victims were still hospitalized Wednesday.

Julie Wylie said five were in stable condition and one was in critical condition.

Calls from The Associated Press about other injured passengers, who were taken to Wilford Hall Medical Center, Brooke Army Medical Center and South Texas Regional Medical Center, were not immediately returned Wednesday

The Americanos USA bus had left San Antonio and was headed for Matamoros, Mexico with a scheduled stop in Falfurrias.

Investigators said Wednesday a broken drive shaft likely caused the crash.

Mange said Wednesday the preliminary investigation shows the drive shaft came apart and fell off of the bus.

The bus driver told investigators she heard a loud noise before the bus veered from the right lane of the highway, spun toward the grassy median and landed on its right side.

The 15-year-old bus underwent its regularly scheduled maintenance the day before the crash, said Bonnie Bastian with FirstGroup America, the parent company of Dallas-based Greyhound Lines, whch operates Americanos USA.

Bastian said the regular inspection covered the engine, tires,
brakes and wheels.